From here: Sam's Laser FAQ - Carbon Dioxide Lasers
There’s no problem with absorption of light from either a Nd:YAG (1.06 microns)
or CO2 (10.6 microns) laser in nitrogen, or in air without contaminants. In
practice, air has variable percentages of CO2 and water vapor and also tends
to contain hydrocarbons, all of which absorb 10.6 um light.
@fablab_elpaso, do you work in a humid atmosphere?
Since the power will be a function of distance it should be easy to compensate for it in software.